This invention relates to an Asynchronous Transfer Mode(ATM) exchange, and, more particularly, to a switch controlling apparatus for small capacitance ATM exchange wherein, in the ATM exchange which receives fixed lengths of data being called cells from a plurality of Line Interface Modules(LIMs) and transfer the data proper output terminal, thereby exchanging a signal, when the ATM exchange receives the cell data from the LIMs, the ATM exchange makes a switch to process data without data collision, thereby simplifying the switch circuit and enhancing reliability thereof.
In general, an ATM exchange has a switch connected to a plurality of LIMs. Conventionally, an arbitrator is used as means for causing the switch to receive cell data from the LIMs without collision therebetween.
There is shown in FIG. 1 a schematic structure for the ATM exchange which comprises a plurality of LIMs 1 connected to the outside of the ATM exchange, a switch module 2 transferring the cell data from the LIMs1 through output ports thereof(not shown) to other apparatus, and a control module connected to the switch module 2 and for performing various control functions. As shown in the drawing, the switch module 2 is connected to numerous LIMs 1 proportional to data processing capacitance thereof.
In the ATM exchange, however, various conditions such as existence and nonexistence of a cell, a priority of a cell, etc. must be considered for efficient management of inputted cells, thereby making constitution of the arbitrator complex and occurring a signal delay as the result of that.
Also, in the U.S. Pat. No. 5,663,959 there is disclosed an ATM cell switching apparatus which serve to prevent degradation of user cells in the ATM switch and preserve the quality of control cells, even upon increase in the number of control cells, in which comprises input cell management means for discriminating a type of cell coming through each input cell highway, distributing user cells and control cells to said ATM switch and control cell processing unit respectively; and output cell management means for discriminating an idle cell output from said ATM switch, inserting a control cell output from said control cell processing unit into a position of discriminated idle cell, and ouputting cells to each said output cell highway.
The patent shows that the control cell to be processed by the ATM switch is dropped in the control cell processing unit and an idle cell output instruction signal is provided from the control cell FIFO in order to preserve the quality of the output control cells and prevent degradation of user cells in the ATM switch, even upon increase in the number of control cells. However as the patent has complex constitution to process input cells, this apparatus is also noneffective as the above prior art.
Therefore, when rate of the cell data to be inputted to the switch module is low, the applicant pays attention to that it is efficient to connect sequentially the cell data to the switch module and process the same without using complex arbitrators.
In view of the foregoing, it is an object of this invention to provide a switch controlling apparatus for small capacitance ATM exchange which connects sequentially a plurality of LIMs to the switch module at integer times rate of input cells rate, processes data to be inputted to the apparatus without data collision as simple structure and thereby enhance the stability of the apparatus performance.
In accordance with one aspect of the invention, there is provided a small capacitance ATM exchange comprising a plurality of LIMs connected to the outside of the ATM exchange, a switch module transferring the cell data from the LIMs through output ports thereof to other apparatus, and a control module connected to the switch module and for performing various control functions characterized in that; the LIMs being for controlling switching of the ATM exchange and comprises a plurality of storage means for storing cell data inputted from an outside apparatus, and a plurality of self order comparators for determining whether the cell data through a control bus from the switch module is mine and producing an enable signal when the cell data is determined to mine.
In accordance with another aspect of the invention, there is provided a small capacitance ATM exchange comprising a plurality of LIMs connected to the outside of the ATM exchange, a switch module transferring the cell data from the LIMs through output ports thereof to other apparatus, and a control module connected to the switch module and for performing various control functions characterized in that; the LIMs being for controlling switching of the ATM exchange and comprises a plurality of storage means for storing cell data inputted from an outside apparatus and transmitting the cell data to a plurality of arbitrators and said each arbitrators being for receiving from a signal from said storage means and for providing each enable signal thereto for causing said storage means to send a data to the switch module.